The objectives of this program are to investigate the metabolism of mucopolysaccharides (glycosaminoglycans) with the eventual aim of facilitating a better understanding of the pathogenesis of connective tissue disease and a better understanding of the processes of development and aging of connective tissues: 1) Biosynthesis of mucopolysaccharides: Microsomal preparations from mouse mast cell tumors are being utilized with appropriate radioactively-labeled sugar nucleotide precursors and PAPS to delineate the pathway of heparin (and related compound) biosynthesis. Microsomal preparations from chick embryo cartilage are being utilized with sugar neuclotide precursors and PAPS to delineate the pathway of chondroitin sulfate biosynthesis. 2) Cellular biology of mucopolysaccharide metabolism: Tissue cultures of mast cells, which produce both heparin and chondroitin sulfate, are being utilized to investigate the subcellular sites of glycosaminoglycan biosynthesis and to follow the processes of packaging and export of the finished compounds. Radioactive precursors will be utilized to pre-label the cells before obtaining subcellular fractions. The fractions will be investigated to determine subcellular sites for glycosaminoglycan metabolism. 3) Metabolism of mucopolysaccharides during growth and differentiation of connective tissue. The metamorphosing tadpole is being used as a model for the study of glycosaminoglycan degradation during rapid connective tissue change. Sub-cellular localization and characterization of the enzymes involved will be undertaken. Biosynthesis and turnover of the glycosaminoglycans during metamorphosis will be investigated.